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.TH CURLMOPT_SOCKETDATA 3 "December 04, 2023" "ibcurl 8.5.0" libcurl

.SH NAME
CURLMOPT_SOCKETDATA \- custom pointer passed to the socket callback
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_SOCKETDATA, void *pointer);
.SH DESCRIPTION
A data \fIpointer\fP to pass to the socket callback set with the
\fICURLMOPT_SOCKETFUNCTION(3)\fP option.

This pointer is not touched by libcurl but is only passed in as the socket
callbacks's \fBclientp\fP argument.
.SH DEFAULT
NULL
.SH PROTOCOLS
All
.SH EXAMPLE
.nf
struct priv {
  void *ours;
};

static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
{
  struct priv *p = sockp;
  printf("my ptr: %p\\n", p->ours);

  if(what == CURL_POLL_REMOVE) {
    /* remove the socket from our collection */
  }
  if(what & CURL_POLL_IN) {
    /* wait for read on this socket */
  }
  if(what & CURL_POLL_OUT) {
    /* wait for write on this socket */
  }

  return 0;
}

int main(void)
{
  struct priv setup;
  CURLM *multi = curl_multi_init();
  /* ... use socket callback and custom pointer */
  curl_multi_setopt(multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
  curl_multi_setopt(multi, CURLMOPT_SOCKETDATA, &setup);
}
.fi
.SH AVAILABILITY
Added in 7.15.4
.SH RETURN VALUE
Returns CURLM_OK.
.SH "SEE ALSO"
.BR curl_multi_socket_action (3),
.BR CURLMOPT_SOCKETFUNCTION (3),
.BR CURLMOPT_TIMERFUNCTION (3)
